The increasing use in recent years of silver halide photographic materials has resulted in a need for rapid processing of such materials. This trend is seen, for example, in the field of medical X-ray photographic films. As the number of X-ray diagnoses associated with health examinations increases, the number of X-ray photographs increases also. At the same time, the necessity of obtaining the results of the diagnoses as soon as possible has placed a premium on rapid photographic processing.
To process large amounts of photographic materials and do it rapidly, it is necessary to decrease the replenishing amount of each processing solution and to shorten the processing time for the development, fixing, washing and drying steps.
Decreasing the replenishing amounts and the time for each processing step leads to problems recognized in the art. These include: (1) developer fatigue; (2) residual color formation due to the hindrance of the desorption of dyes; and (3) inadequate fixing. These problems cannot be ignored.
The use of iodine or an iodine ion is one recognized means of addressing some of the problems inherent in rapid processing. However, the use of iodine has its own set of problems. When an iodine ion is used to lower developer fatigue and the development restraining action, the amount of developer replenisher must be increased. Also, as described for example in JP-A-2-68540 (The term "JP-A" as used herein means an unexamined published Japanese patent application), while iodine improves the adsorption of dyes, it increases residual color formation associated with spectral sensitizing dyes. To prevent this increase in residual color formation, the processing times for fixing and washing must be increased. This is same as to inadequate fixing.
Despite the problems associated with the use of iodine, the general outlook in the art has been that iodine is an essential component in silver halide emulsions, and, in particular, in silver halide emulsions that are highly sensitive, have excellent development properties, and are rapidly processable. This is described, for example, in JP-B-63-38692 (The term "JP-B" as used herein means an examined Japanese patent publication) and JP-A-63-305343.